Electrodeposition of CuInSe2 Photovoltaic Thin Films and Growth Morphology

$CuInSe_2$ (CIS) thin films were electrodeposited on Mo-coated glass substrates in acidic solutions containing $Cu^{2+}$, $In^{3+}$, and $Se^{4+}$ ions, depending on deposition parameters such as deposition potential (-0.4 to -0.8 V[SCE]) and pH (1.7 to 1.9). The influences of PH and deposition potential on the atomic composition of Cu, In, and Se in the deposited films were observed. The best chemical composition, approaching 1:1:2 atomic ratio for the elements, was achieved at -0.5 V (SCE) and pH 1.8. The as-deposited films showed low crystallinity and were annealed at 300 to $500^{\circ}C$ for 30 min to improve crystallization. The surface morphologies, microstructures, and crystallographic structures of the annealed films as well as the as-deposited films were analyzed with AFM, SEM, and XRD. The defects of spherical particles appeared on the surfaces of CIS thin films in the as-deposited state and decreased in size and number with increasing annealing temperatures. Additionally, the crystallization to chalcopyrite structure and surface roughness (Ra) of the as-deposited thin films were improved with the annealing process.

CuInSe2 태양전지 박막의 전해증착 및 성장형상